Magnetic field sensors for detecting magnetic fields are known. In a magnetic field sensor, the magnetic field is detected by a magnetic field sensing element, such as a Hall element or a magnetoresistance element, which provides a signal (i.e., a magnetic field signal) proportional to a detected magnetic field. In some arrangements, the magnetic field signal is an electrical signal.
Magnetic field sensors are used in a variety of applications, including, but not limited to, a linear magnetic field sensor that senses a magnetic field density of a magnetic field, a current sensor that senses a magnetic field generated by a current flowing in a current carrying conductor, a magnetic switch that senses the proximity of a ferromagnetic object, and a rotation detector that senses passing ferromagnetic articles.
For a linear magnetic field sensor, the output signal changes in direct proportion to the sensed magnetic field. For a magnetic switch, the output signal changes state in response to the sensed magnetic field.
Magnetic field sensors are subject to noise, which tends to degrade the accuracy of the magnetic field sensors. The noise can come from a variety of noise sources, including, but not limited to, sources of external magnetic noise fields and sources of external electric noise fields.
It would be desirable to have a magnetic field sensor for which the noise can be distinguished (discriminated) from a desired magnetic field signal.